U.S. patent number 8,345,381 [Application Number 13/456,914] was granted by the patent office on 2013-01-01 for magnetic head for perpendicular magnetic recording having a return path section.
This patent grant is currently assigned to Headway Technologies, Inc., SAE Magnetics (H.K.) Ltd.. Invention is credited to Hironori Araki, Hiroyuki Ito, Yoshitaka Sasaki, Kazuki Sato, Tatsuya Shimizu, Shigeki Tanemura, Seiichiro Tomita.
United States Patent |
8,345,381 |
Sasaki , et al. |
January 1, 2013 |
Magnetic head for perpendicular magnetic recording having a return
path section
Abstract
A magnetic head includes a coil, a main pole, a shield, a return
path section, and an accommodation part that are disposed above the
top surface of a substrate. The accommodation part accommodates at
least part of the return path section. The return path section lies
between the main pole and the top surface of the substrate, and
connects the shield and part of the main pole away from a medium
facing surface to each other so that a space through which part of
the coil passes is defined. The accommodation part includes an
interposer interposed between the return path section and the
medium facing surface. The interposer has an inclined surface
facing toward the return path section. The return path section
includes an inclined portion located between part of the coil and
the inclined surface and extending along the inclined surface.
Inventors: |
Sasaki; Yoshitaka (Santa Clara,
CA), Ito; Hiroyuki (Milpitas, CA), Araki; Hironori
(Milpitas, CA), Tomita; Seiichiro (Milpitas, CA), Sato;
Kazuki (Milpitas, CA), Tanemura; Shigeki (Milpitas,
CA), Shimizu; Tatsuya (Hong Kong, CN) |
Assignee: |
Headway Technologies, Inc.
(Milpitas, CA)
SAE Magnetics (H.K.) Ltd. (Hong Kong, CN)
|
Family
ID: |
47388311 |
Appl.
No.: |
13/456,914 |
Filed: |
April 26, 2012 |
Current U.S.
Class: |
360/123.03;
360/125.02 |
Current CPC
Class: |
G11B
5/1278 (20130101); G11B 5/315 (20130101); G11B
5/17 (20130101); G11B 5/3116 (20130101); G11B
5/3163 (20130101) |
Current International
Class: |
G11B
5/17 (20060101); G11B 5/147 (20060101) |
Field of
Search: |
;360/123.03,123.06,123.1,125.02,125.16,125.17,125.3 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
US. Appl. No. 13/456,932, filed Apr. 26, 2012 in the name of
Yoshitaka Sasaki et al. cited by other.
|
Primary Examiner: Miller; Brian
Attorney, Agent or Firm: Oliff & Berridge, PLC
Claims
What is claimed is:
1. A magnetic head for perpendicular magnetic recording,
comprising: a medium facing surface that faces a recording medium;
a coil that produces a magnetic field corresponding to data to be
written on the recording medium; a main pole that has an end face
located in the medium facing surface, the main pole allowing a
magnetic flux that corresponds to the magnetic field produced by
the coil to pass, and producing a write magnetic field for writing
the data on the recording medium by means of a perpendicular
magnetic recording system; a write shield made of a magnetic
material and having an end face located in the medium facing
surface; a gap part made of a nonmagnetic material and interposed
between the main pole and the write shield; a first return path
section made of a magnetic material; an accommodation part made of
a nonmagnetic material and accommodating at least part of the first
return path section; and a substrate having a top surface, wherein:
the coil, the main pole, the write shield, the gap part, the first
return path section, and the accommodation part are located above
the top surface of the substrate; the end face of the write shield
includes: a first end face portion located on a front side in a
direction of travel of the recording medium relative to the end
face of the main pole; and a second end face portion located on a
rear side in the direction of travel of the recording medium
relative to the end face of the main pole; the first return path
section is located on the rear side in the direction of travel of
the recording medium relative to the main pole and lies between the
main pole and the top surface of the substrate, the first return
path section connecting the write shield and part of the main pole
away from the medium facing surface to each other so that a first
space is defined by the main pole, the gap part, the write shield,
and the first return path section; the coil includes at least one
first coil element extending to pass through the first space; the
accommodation part includes an interposer interposed between the
first return path section and the medium facing surface; the
interposer has an inclined surface facing toward the first return
path section; a distance from the medium facing surface to an
arbitrary point on the inclined surface decreases with increasing
distance from the arbitrary point to the top surface of the
substrate; and the first return path section includes an inclined
portion located between the at least one first coil element and the
inclined surface and extending along the inclined surface.
2. The magnetic head for perpendicular magnetic recording according
to claim 1, wherein the interposer is made of an inorganic
insulating material.
3. The magnetic head for perpendicular magnetic recording according
to claim 1, wherein the inclined surface forms a first angle of
5.degree. to 45.degree. relative to a direction perpendicular to
the top surface of the substrate.
4. The magnetic head for perpendicular magnetic recording according
to claim 1, wherein: the inclined portion has a first end face
facing toward the medium facing surface and a second end face in
contact with the write shield; the first end face has an end
located in the medium facing surface; and when seen at the end of
the first end face, the first end face forms a second angle greater
than 90.degree. relative to a part of the medium facing surface,
the part of the medium facing surface being located on the front
side in the direction of travel of the recording medium relative to
the end of the first end face.
5. The magnetic head for perpendicular magnetic recording according
to claim 4, wherein the second angle is equal to 180.degree. minus
the first angle.
6. The magnetic head for perpendicular magnetic recording according
to claim 4, wherein the second angle is smaller than 180.degree.
minus the first angle.
7. The magnetic head for perpendicular magnetic recording according
to claim 1, further comprising a second return path section located
on the front side in the direction of travel of the recording
medium relative to the main pole, the second return path section
connecting the write shield and part of the main pole away from the
medium facing surface to each other so that a second space is
defined by the main pole, the gap part, the write shield, and the
second return path section, wherein the coil further includes at
least one second coil element extending to pass through the second
space.
8. The magnetic head for perpendicular magnetic recording according
to claim 1, wherein the end face of the write shield further
includes a third end face portion and a fourth end face portion,
the third end face portion and the fourth end face portion being
located on opposite sides of the end face of the main pole in a
track width direction.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic head for perpendicular
magnetic recording that is used for writing data on a recording
medium by means of a perpendicular magnetic recording system, and
more specifically, to a magnetic head for perpendicular magnetic
recording that has a main pole, a shield, and a return path
section.
2. Description of Related Art
The recording systems of magnetic read/write apparatuses include a
longitudinal magnetic recording system wherein signals are
magnetized in a direction along the plane of the recording medium
(the longitudinal direction) and a perpendicular magnetic recording
system wherein signals are magnetized in a direction perpendicular
to the plane of the recording medium. It is known that the
perpendicular magnetic recording system is harder to be affected by
thermal fluctuation of the recording medium and capable of
providing higher linear recording density, compared with the
longitudinal magnetic recording system.
Magnetic heads for perpendicular magnetic recording typically have,
like those for longitudinal magnetic recording, a structure where a
read head section having a magnetoresistive element (hereinafter,
also referred to as MR element) for reading and a write head
section having an induction-type electromagnetic transducer for
writing are stacked on the top surface of a substrate. The write
head section includes a main pole that produces a write magnetic
field in a direction perpendicular to the plane of the recording
medium. The main pole includes, for example, a track width defining
portion having an end located in a medium facing surface that faces
the recording medium, and a wide portion that is connected to the
other end of the track width defining portion and is greater in
width than the track width defining portion. The track width
defining portion has a generally constant width. To achieve higher
recording density, it is required that the write head section of
the perpendicular magnetic recording system be smaller in track
width and improved in write characteristics such as overwrite
property which is a parameter indicating an overwriting
capability.
A magnetic head for use in a magnetic disk drive such as a hard
disk drive is typically provided in a slider. The slider has the
medium facing surface mentioned above. The medium facing surface
has an air inflow end (a leading end) and an air outflow end (a
trailing end). The slider is designed to slightly fly over the
surface of the recording medium by means of an airflow that comes
from the air inflow end into the space between the medium facing
surface and the recording medium.
Here, the side of the positions closer to the leading end relative
to a reference position will be defined as the leading side, and
the side of the positions closer to the trailing end relative to
the reference position will be defined as the trailing side. The
leading side is the rear side in the direction of travel of the
recording medium relative to the slider. The trailing side is the
front side in the direction of travel of the recording medium
relative to the slider.
The magnetic head is typically disposed near the trailing end of
the medium facing surface of the slider. In a magnetic disk drive,
positioning of the magnetic head is performed by a rotary actuator,
for example. In this case, the magnetic head moves over the
recording medium along a circular orbit about the center of
rotation of the rotary actuator. In such a magnetic disk drive, a
tilt of the magnetic head with respect to the tangent of the
circular track, which is called a skew, occurs according to the
position of the magnetic head across the tracks.
In particular, in a magnetic disk drive of the perpendicular
magnetic recording system which is higher in capability of writing
on a recording medium than the longitudinal magnetic recording
system, the skew mentioned above can cause the phenomenon that
signals already written on one or more tracks that are adjacent to
a track targeted for writing are erased or attenuated during
writing of a signal on the track targeted for writing (such a
phenomenon will hereinafter be referred to as adjacent track
erasure). For higher recording densities, it is necessary to
prevent adjacent track erasure.
Providing a write shield near the main pole is effective for
preventing adjacent track erasure induced by the skew mentioned
above and increasing the recording density. For example, U.S. Pat.
No. 6,954,340 B2 and U.S. Patent Application Publication No.
2005/0128637 A1 describe a magnetic head including a write shield
having an end face that is located in the medium facing surface to
wrap around an end face of the main pole.
A magnetic head including a write shield is typically provided with
one or more return path sections for connecting the write shield to
a part of the main pole away from the medium facing surface. The
write shield and the one or more return path sections have the
function of capturing a magnetic flux that is produced from the end
face of the main pole and spreads in directions other than the
direction perpendicular to the plane of the recording medium, so as
to prevent the magnetic flux from reaching the recording medium.
The write shield and the one or more return path sections also have
the function of allowing a magnetic flux that has been produced
from the end face of the main pole and has magnetized the recording
medium to flow back to the main pole. Thus, the magnetic head
including the write shield makes it possible to prevent adjacent
track erasure and allows a further improvement of the recording
density.
U.S. Pat. No. 6,954,340 B2 and U.S. Patent Application Publication
No. 2005/0128637 A1 each disclose a magnetic head including, as the
aforementioned one or more return path sections, a return path
section located on the trailing side relative to the main pole and
a return path section located on the leading side relative to the
main pole.
Now, the configuration of the return path section located on the
leading side relative to the main pole (hereinafter, referred to as
the leading return path section) will be contemplated. In a
magnetic head, the read head section and the write head section
stacked on the top surface of the substrate are typically located
on the trailing side relative to the top surface of the substrate.
In this case, the leading return path section lies between the main
pole and the top surface of the substrate. The main pole and the
leading return path section define a space through which a portion
of a coil passes. In such a magnetic head, the leading return path
section is typically configured to have a first layer, a second
layer formed on the first layer at a position near the medium
facing surface, and a third layer formed on the first layer at a
position away from the medium facing surface. The second layer
connects a part of the first layer located near the medium facing
surface to the write shield. The third layer connects a part of the
first layer located away from the medium facing surface to a part
of the main pole located away from the medium facing surface.
In the magnetic head shown in FIG. 8 of U.S. Patent Application
Publication No. 2005/0128637 A1, a return pole located on the
leading side relative to the main pole corresponds to the
aforementioned first layer, a shorting shield located on the
leading side relative to the main pole corresponds to part of the
write shield and the aforementioned second layer, and a back via
located on the leading side relative to the main pole corresponds
to the aforementioned third layer.
In the typical configuration of the leading return path section
described above, the second layer is extremely longer in the
direction of travel of the recording medium than in the direction
perpendicular to the medium facing surface, and an end face of the
second layer is exposed over a large area in the medium facing
surface. When the second layer has such a configuration, part of
the magnetic flux captured into the second layer from a part of the
end face of the second layer located near the end face of the main
pole may leak from another part of the end face of the second layer
toward the recording medium. This may result in the occurrence of
adjacent track erasure.
Furthermore, when the leading return path section has the typical
configuration described above, heat generated by the coil may cause
expansion of the second layer and an insulating layer surrounding
the coil, and thereby cause the end face of the second layer to
protrude toward the recording medium. The protrusion of the end
face of the second layer causes the end face of the main pole and
an end of the read head section located in the medium facing
surface to get farther from the recording medium, and this may
result in degradation of the read and write characteristics.
OBJECT AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a magnetic head
for perpendicular magnetic recording that can avoid the problems
resulting from a configuration in which an end face of a return
path section located on the rear side in the direction of travel of
the recording medium relative to the main pole is exposed over a
large area in the medium facing surface.
A magnetic head for perpendicular magnetic recording of the present
invention includes: a medium facing surface that faces a recording
medium; a coil; a main pole; a write shield; a gap part; a first
return path section made of a magnetic material; an accommodation
part; and a substrate having a top surface. The coil produces a
magnetic field corresponding to data to be written on the recording
medium. The main pole has an end face located in the medium facing
surface. The main pole allows a magnetic flux corresponding to the
magnetic field produced by the coil to pass, and produces a write
magnetic field for writing the data on the recording medium by
means of a perpendicular magnetic recording system. The write
shield is made of a magnetic material and has an end face located
in the medium facing surface. The gap part is made of a nonmagnetic
material and interposed between the main pole and the write shield.
The accommodation part is made of a nonmagnetic material and
accommodates at least part of the first return path section. The
coil, the main pole, the write shield, the gap part, the first
return path section, and the accommodation part are located above
the top surface of the substrate.
The end face of the write shield includes: a first end face portion
located on the front side in the direction of travel of the
recording medium relative to the end face of the main pole; and a
second end face portion located on the rear side in the direction
of travel of the recording medium relative to the end face of the
main pole. The first return path section is located on the rear
side in the direction of travel of the recording medium relative to
the main pole and lies between the main pole and the top surface of
the substrate. The first return path section connects the write
shield and part of the main pole away from the medium facing
surface to each other so that a first space is defined by the main
pole, the gap part, the write shield, and the first return path
section. The coil includes at least one first coil element
extending to pass through the first space.
The accommodation part includes an interposer interposed between
the first return path section and the medium facing surface. The
interposer has an inclined surface facing toward the first return
path section. The distance from the medium facing surface to an
arbitrary point on the inclined surface decreases with increasing
distance from the arbitrary point to the top surface of the
substrate. The first return path section includes an inclined
portion located between the at least one first coil element and the
inclined surface and extending along the inclined surface.
In the magnetic head for perpendicular magnetic recording of the
present invention, the interposer may be made of an inorganic
insulating material. The inclined surface may form a first angle of
5.degree. to 45.degree. relative to a direction perpendicular to
the top surface of the substrate.
In the magnetic head for perpendicular magnetic recording of the
present invention, the inclined portion may have a first end face
facing toward the medium facing surface and a second end face in
contact with the write shield. The first end face may have an end
located in the medium facing surface. In this case, when seen at
the end of the first end face, the first end face may form a second
angle greater than 90.degree. relative to a part of the medium
facing surface, the part of the medium facing surface being located
on the front side in the direction of travel of the recording
medium relative to the end of the first end face. The second angle
may be equal to 180.degree. minus the first angle, or may be
smaller than 180.degree. minus the first angle.
The magnetic head for perpendicular magnetic recording of the
present invention may further include a second return path section
located on the front side in the direction of travel of the
recording medium relative to the main pole. The second return path
section connects the write shield and part of the main pole away
from the medium facing surface to each other so that a second space
is defined by the main pole, the gap part, the write shield, and
the second return path section. In this case, the coil may further
include at least one second coil element extending to pass through
the second space.
In the magnetic head for perpendicular magnetic recording of the
present invention, the end face of the write shield may further
include a third end face portion and a fourth end face portion. The
third end face portion and the fourth end face portion may be
located on opposite sides of the end face of the main pole in the
track width direction.
In the magnetic head for perpendicular magnetic recording of the
present invention, the accommodation part includes the interposer
interposed between the first return path section and the medium
facing surface. The interposer has the inclined surface facing
toward the first return path section, and the first return path
section includes the inclined portion extending along the inclined
surface. These features of the present invention make it possible
to connect the first return path section to the write shield
without causing the end face of the first return path section to be
exposed over a large area in the medium facing surface.
Consequently, according to the present invention, it is possible to
avoid the problems resulting from the configuration in which the
end face of the first return path section is exposed over a large
area in the medium facing surface.
Other objects, features and advantages of the present invention
will become fully apparent from the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a magnetic head according to a
first embodiment of the invention.
FIG. 2 is a front view showing the medium facing surface of the
magnetic head according to the first embodiment of the
invention.
FIG. 3 is a plan view showing a first portion of a coil of the
magnetic head according to the first embodiment of the
invention.
FIG. 4 is a plan view showing a first layer of a second portion of
the coil of the magnetic head according to the first embodiment of
the invention.
FIG. 5 is a plan view showing a second layer of the second portion
of the coil of the magnetic head according to the first embodiment
of the invention.
FIG. 6 is a cross-sectional view showing a part of a main pole in
the vicinity of the medium facing surface in the magnetic head
according to the first embodiment of the invention.
FIG. 7A and FIG. 7B are explanatory diagrams illustrating the
function of the interposer of the accommodation part of the first
embodiment of the invention.
FIG. 8A and FIG. 8B are cross-sectional views showing a step of a
method of manufacturing the magnetic head according to the first
embodiment of the invention.
FIG. 9A and FIG. 9B are cross-sectional views showing a step that
follows the step shown in FIG. 8A and FIG. 8B.
FIG. 10A and FIG. 10B are cross-sectional views showing a step that
follows the step shown in FIG. 9A and FIG. 9B.
FIG. 11A and FIG. 11B are cross-sectional views showing a step that
follows the step shown in FIG. 10A and FIG. 10B.
FIG. 12A and FIG. 12B are cross-sectional views showing a step that
follows the step shown in FIG. 11A and FIG. 11B.
FIG. 13A and FIG. 13B are cross-sectional views showing a step that
follows the step shown in FIG. 12A and FIG. 12B.
FIG. 14A and FIG. 14B are cross-sectional views showing a step that
follows the step shown in FIG. 13A and FIG. 13B.
FIG. 15A and FIG. 15B are cross-sectional views showing a step that
follows the step shown in FIG. 14A and FIG. 14B.
FIG. 16A and FIG. 16B are cross-sectional views showing a step that
follows the step shown in FIG. 15A and FIG. 15B.
FIG. 17A and FIG. 17B are cross-sectional views showing a step that
follows the step shown in FIG. 16A and FIG. 16B.
FIG. 18A and FIG. 18B are cross-sectional views showing a step that
follows the step shown in FIG. 17A and FIG. 17B.
FIG. 19A and FIG. 19B are cross-sectional views showing a step that
follows the step shown in FIG. 18A and FIG. 18B.
FIG. 20A and FIG. 20B are cross-sectional views showing a step that
follows the step shown in FIG. 19A and FIG. 19B.
FIG. 21A and FIG. 21B are cross-sectional views showing a step that
follows the step shown in FIG. 20A and FIG. 20B.
FIG. 22A and FIG. 22B are cross-sectional views showing a step that
follows the step shown in FIG. 21A and FIG. 21B.
FIG. 23A and FIG. 23B are cross-sectional views showing a step that
follows the step shown in FIG. 22A and FIG. 22B.
FIG. 24A and FIG. 24B are cross-sectional views showing a step that
follows the step shown in FIG. 23A and FIG. 23B.
FIG. 25 is a plan view showing a plurality of first coil elements
of a coil of a magnetic head according to a second embodiment of
the invention.
FIG. 26 is a plan view showing a plurality of second coil elements
of the coil of the magnetic head according to the second embodiment
of the invention.
FIG. 27 is a cross-sectional view of a magnetic head according to a
third embodiment of the invention.
FIG. 28 is a cross-sectional view of a magnetic head according to a
fourth embodiment of the invention.
FIG. 29 is a plan view showing a second layer of a second portion
of a coil of the magnetic head according to the fourth embodiment
of the invention.
FIG. 30 is a cross-sectional view of a magnetic head according to a
fifth embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
Embodiments of the present invention will now be described in
detail with reference to the drawings. First, reference is made to
FIG. 1 to FIG. 6 to describe the configuration of a magnetic head
according to a first embodiment of the invention. FIG. 1 is a
cross-sectional view of the magnetic head according to the present
embodiment. FIG. 2 is a front view showing the medium facing
surface of the magnetic head according to the present embodiment.
FIG. 3 is a plan view showing a first portion of a coil of the
magnetic head according to the present embodiment. FIG. 4 is a plan
view showing a first layer of a second portion of the coil of the
magnetic head according to the present embodiment. FIG. 5 is a plan
view showing a second layer of the second portion of the coil of
the magnetic head according to the present embodiment. FIG. 6 is a
cross-sectional view showing a part of a main pole in the vicinity
of the medium facing surface in the magnetic head according to the
present embodiment. Note that FIG. 1 and FIG. 6 show cross sections
perpendicular to the medium facing surface and to the top surface
of the substrate. The arrows with the symbol T in FIG. 1 and FIG. 6
indicate the direction of travel of the recording medium. The
arrows with the symbol TW in FIG. 2 to FIG. 5 indicate the track
width direction.
As shown in FIG. 1 and FIG. 2, the magnetic head for perpendicular
magnetic recording (hereinafter simply referred to as the magnetic
head) according to the present embodiment includes: a substrate 1
made of a ceramic material such as aluminum oxide-titanium carbide
(Al.sub.2O.sub.3--TiC) and having a top surface 1a; an insulating
layer 2 made of an insulating material such as alumina
(Al.sub.2O.sub.3) and disposed on the top surface 1a of the
substrate 1; a first read shield layer 3 made of a magnetic
material and disposed on the insulating layer 2; a first read
shield gap film 4 which is an insulating film disposed to cover the
first read shield layer 3; a magnetoresistive (MR) element 5
serving as a read element disposed on the first read shield gap
film 4; a second read shield gap film 6 which is an insulating film
disposed on the MR element 5; and a second read shield layer 7 made
of a magnetic material and disposed on the second read shield gap
film 6.
An end of the MR element 5 is located in a medium facing surface 80
that faces the recording medium. The MR element 5 may be an element
formed of a magneto-sensitive film that exhibits a magnetoresistive
effect, such as an anisotropic magnetoresistive (AMR) element, a
giant magnetoresistive (GMR) element, or a tunneling
magnetoresistive (TMR) element. The GMR element may be of either
the current-in-plane (CIP) type in which a current for use in
magnetic signal detection is fed in a direction generally parallel
to the plane of layers constituting the GMR element or the
current-perpendicular-to-plane (CPP) type in which the current for
use in magnetic signal detection is fed in a direction generally
perpendicular to the plane of the layers constituting the GMR
element.
The parts from the first read shield layer 3 to the second read
shield layer 7 constitute a read head section 8. The magnetic head
further includes: a nonmagnetic layer 71 made of a nonmagnetic
material and disposed on the second read shield layer 7; a middle
shield layer 72 made of a magnetic material and disposed on the
nonmagnetic layer 71; and a write head section 9 disposed on the
middle shield layer 72. The middle shield layer 72 has the function
of shielding the MR element 5 from magnetic fields generated in the
write head section 9. The nonmagnetic layer 71 is made of alumina,
for example. The write head section 9 includes a coil, a main pole
15, a write shield 16, and a gap part 17.
The coil produces a magnetic field corresponding to data to be
written on the recording medium. The coil includes a first portion
10 and a second portion 20. The first portion 10 and the second
portion 20 are both made of a conductive material such as copper.
The first portion 10 and the second portion 20 are connected in
series or in parallel. The main pole 15 has an end face located in
the medium facing surface 80. The main pole 15 allows a magnetic
flux corresponding to the magnetic field produced by the coil to
pass, and produces a write magnetic field for writing data on the
recording medium by means of a perpendicular magnetic recording
system. FIG. 1 and FIG. 6 each show a cross section that intersects
the end face of the main pole 15 located in the medium facing
surface 80 and that is perpendicular to the medium facing surface
80 and to the top surface 1a of the substrate 1 (the cross section
will hereinafter be referred to as the main cross section). The
write shield 16 has an end face located in the medium facing
surface 80. The end face of the write shield 16 includes first to
fourth end face portions 16Aa, 16Ba, 16Ca, and 16Da. The first end
face portion 16Aa is located on the front side in the direction T
of travel of the recording medium relative to the end face of the
main pole 15. The second end face portion 16Ba is located on the
rear side in the direction T of travel of the recording medium
relative to the end face of the main pole 15. The third and fourth
end face portions 16Ca and 16Da are located on opposite sides of
the end face of the main pole 15 in the track width direction TW.
In the medium facing surface 80, the first to fourth end face
portions 16Aa, 16Ba, 16Ca, and 16Da are arranged to wrap around the
end face of the main pole 15.
The write shield 16 is made of a magnetic material. Examples of
materials that can be used for the write shield 16 include CoFeN,
CoNiFe, NiFe, and CoFe.
The write head section 9 further includes a first return path
section 30 and a second return path section 40. The first and
second return path sections 30 and 40 are both made of a magnetic
material. Examples of materials that can be used for the first and
second return path sections 30 and 40 include CoFeN, CoNiFe, NiFe,
and CoFe. The first return path section 30 and the second return
path section 40 align along a direction perpendicular to the top
surface 1a of the substrate 1 with the main pole 15 interposed
therebetween. The first return path section 30 is located on the
rear side in the direction T of travel of the recording medium
relative to the main pole 15, and connects the write shield 16 and
part of the main pole 15 away from the medium facing surface 80 to
each other, thereby magnetically coupling the write shield 16 and
the main pole 15 to each other. The second return path section 40
is located on the front side in the direction T of travel of the
recording medium relative to the main pole 15, and connects the
write shield 16 and part of the main pole 15 away from the medium
facing surface 80 to each other, thereby magnetically coupling the
write shield 16 and the main pole 15 to each other.
The first return path section 30 includes magnetic layers 31, 32
and 36. The magnetic layer 31 includes a horizontal portion 31A, a
first inclined portion 31B and a second inclined portion 31C. The
horizontal portion 31A extends in a direction parallel to the top
surface 1a of the substrate 1. The first inclined portion 31B
extends from a part of the horizontal portion 31A, the part being
in the vicinity of the end of the horizontal portion 31A closest to
the medium facing surface 80, in the direction away from the top
surface 1a of the substrate 1. The second inclined portion 31C
extends from a part of the horizontal portion 31A, the part being
in the vicinity of the end of the horizontal portion 31A farthest
from the medium facing surface 80, in the direction away from the
top surface 1a of the substrate 1. In the main cross section
mentioned above, the distance between the first inclined portion
31B and the second inclined portion 31C in the direction
perpendicular to the medium facing surface 80 increases with
increasing distance from the top surface 1a of the substrate 1. In
FIG. 1, the boundary between the horizontal portion 31A and the
first inclined portion 31B and the boundary between the horizontal
portion 31A and the second inclined portion 31C are shown by dotted
lines. The first inclined portion 31B has a first end face 31Ba
facing toward the medium facing surface 80 and a second end face
31Bb in contact with the write shield 16. The first inclined
portion 31B corresponds to the "inclined portion" according to the
invention.
The magnetic layer 32 is in contact with the horizontal portion 31A
and the second inclined portion 31C and lies between the first
inclined portion 31B and the second inclined portion 31C with a gap
between the first inclined portion 31B and the magnetic layer 32.
As shown in FIG. 3, the first portion 10 of the coil is wound
approximately three turns around the second inclined portion 31C
and the magnetic layer 32.
The magnetic head further includes an accommodation part 50 made of
a nonmagnetic material and accommodating at least part of the first
return path section 30. In the present embodiment, the
accommodation part 50 accommodates the magnetic layers 31 and 32,
in particular. The accommodation part 50 includes a nonmagnetic
layer 51 and a nonmagnetic film 52. The nonmagnetic layer 51 is
disposed on the middle shield layer 72. The nonmagnetic layer 51
has an opening 51a that penetrates the nonmagnetic layer 51 from
its top surface to bottom surface. The opening 51a has a first wall
face located outside of the outermost turn of the first portion 10
and a second wall face located inside of the innermost turn of the
first portion 10. The first and second wall faces are inclined
relative to the direction perpendicular to the top surface 1a of
the substrate 1. More specifically, in the main cross section, the
distance from the medium facing surface 80 to an arbitrary point on
the first wall face decreases with increasing distance from the
arbitrary point to the top surface 1a of the substrate 1. In the
main cross section, the distance from the medium facing surface 80
to an arbitrary point on the second wall face increases with
increasing distance from the arbitrary point to the top surface 1a
of the substrate 1.
The magnetic layers 31 and 32 and the first portion 10 are located
in the opening 51a of the nonmagnetic layer 51. The nonmagnetic
film 52 is disposed to extend along the top surface of the
nonmagnetic layer 51, the first and second wall faces of the
opening 51a, and the top surface of the middle shield layer 72. The
nonmagnetic layer 51 and the nonmagnetic film 52 are each made of
an inorganic insulating material such as alumina.
The accommodation part 50 includes an interposer 50A interposed
between the first return path section 30 and the medium facing
surface 80. The interposer 50A has an inclined surface 50Aa facing
toward the first return path section 30. The distance from the
medium facing surface 80 to an arbitrary point on the inclined
surface 50Aa decreases with increasing distance from the arbitrary
point to the top surface 1a of the substrate 1. The interposer 50A
is composed of part of the nonmagnetic layer 51 and part of the
nonmagnetic film 52. The first inclined portion 31B extends along
the inclined surface 50Aa.
The magnetic head further includes an electrode film 73 made of a
nonmagnetic metal material and disposed along the nonmagnetic film
52. The electrode film 73 is used as an electrode and seed when the
magnetic layer 31 is formed by plating. The electrode film 73 has a
thickness in the range of 50 to 80 nm, for example. The electrode
film 73 is made of Ru, for example.
The magnetic head further includes an insulating film 53 made of an
insulating material and interposed between the first portion 10 and
the magnetic layers 31 and 32, and an insulating layer 54 made of
an insulating material and disposed in the space between every
adjacent turns of the first portion 10. The top surfaces of the
first portion 10, the magnetic layers 31 and 32, the insulating
film 53, the insulating layer 54 and the electrode film 73 are even
with each other. The insulating film 53 and the insulating layer 54
are made of alumina, for example.
As shown in FIG. 2, the write shield 16 includes a first shield
16A, a second shield 16B, and two side shields 16C and 16D. The two
side shields 16C and 16D are located on opposite sides of the main
pole 15 in the track width direction TW. The first shield 16A is
located on the front side in the direction T of travel of the
recording medium relative to the main pole 15. The second shield
16B is located on the rear side in the direction T of travel of the
recording medium relative to the main pole 15. The side shields 16C
and 16D magnetically couple the first shield 16A and the second
shield 16B to each other.
As shown in FIG. 6, the first shield 16A includes: the first end
face portion 16Aa; a first inclined surface 16Ab which is a bottom
surface; a top surface 16Ac; and a connecting surface 16Ad which
connects the first end face portion 16Aa and the top surface 16Ac
to each other. The distance from the medium facing surface 80 to an
arbitrary point on the connecting surface 16Ad increases with
increasing distance from the arbitrary point to the top surface 1a
of the substrate 1. The second shield 16B includes the second end
face portion 16Ba, and a top surface including a second inclined
surface 16Bb. The first inclined surface 16Ab and the second
inclined surface 16Bb will be described in detail later. As shown
in FIG. 2, the side shield 16C includes the third end face portion
16Ca. The side shield 16D includes the fourth end face portion
16Da.
The second shield 16B is disposed on the first inclined portion 31B
of the magnetic layer 31 and in contact with the second end face
31Bb of the first inclined portion 31B. The magnetic layer 36 is
disposed over the second inclined portion 31C of the magnetic layer
31 and the magnetic layer 32. The magnetic head further includes:
an insulating layer 55 made of an insulating material, disposed
over the top surfaces of the first portion 10, the insulating film
53 and the insulating layer 54 and surrounding the second shield
16B and the magnetic layer 36; and a nonmagnetic layer 56 made of a
nonmagnetic material and disposed over the insulating layer 55 and
the electrode film 73. The insulating layer 55 and the nonmagnetic
layer 56 are made of alumina, for example.
The main pole 15 has a top surface 15T (see FIG. 6), which is a
surface located at an end on the front side in the direction T of
travel of the recording medium, and a bottom end 15L (see FIG. 6)
opposite to the top surface 15T. The main pole 15 further has first
and second side parts (see FIG. 2) that are opposite to each other
in the track width direction TW. The side shield 16C has a first
sidewall opposed to the first side part of the main pole 15. The
side shield 16D has a second sidewall opposed to the second side
part of the main pole 15.
The gap part 17 is made of a nonmagnetic material and interposed
between the main pole 15 and the write shield 16. The gap part 17
includes a first gap layer 19 interposed between the main pole 15
and the first shield 16A, and a second gap layer 18 interposed
between the main pole 15 and each of the second shield 16B and the
side shields 16C and 16D.
The side shields 16C and 16D are disposed on the second shield 16B
and in contact with the top surface of the second shield 16B. The
second gap layer 18 is arranged to extend along the sidewalls of
the side shields 16C and 16D, the top surface of the second shield
16B and the top surface of the nonmagnetic layer 56. The
nonmagnetic material employed to form the second gap layer 18 may
be an insulating material or a nonmagnetic metal material. Alumina
is an example of insulating materials that can be used to form the
second gap layer 18. Ru is an example of nonmagnetic metal
materials that can be used to form the second gap layer 18.
The main pole 15 is disposed over the second shield 16B and the
nonmagnetic layer 56 such that the second gap layer 18 is
interposed between the main pole 15 and the top surfaces of the
second shield 16B and the nonmagnetic layer 56. As shown in FIG. 2,
the second gap layer 18 is interposed also between the main pole 15
and each of the side shields 16C and 16D.
The bottom end 15L of the main pole 15 is in contact with the top
surface of the magnetic layer 36 at a position away from the medium
facing surface 80. The main pole 15 is made of a magnetic metal
material. Examples of materials that can be used for the main pole
15 include NiFe, CoNiFe, and CoFe. The shape of the main pole 15
will be described in detail later.
The magnetic head further includes a nonmagnetic layer 57 made of a
nonmagnetic material and disposed around the main pole 15 and the
side shields 16C and 16D. The nonmagnetic layer 57 is made of
alumina, for example.
The magnetic head further includes: a nonmagnetic metal layer 58
made of a nonmagnetic metal material and disposed on part of the
top surface 15T of the main pole 15 at a position away from the
medium facing surface 80; and an insulating layer 59 made of an
insulating material and disposed on the top surface of the
nonmagnetic metal layer 58. The nonmagnetic metal layer 58 is made
of Ru, NiCr, or NiCu, for example. The insulating layer 59 is made
of alumina, for example.
The first gap layer 19 is disposed to cover the main pole 15, the
nonmagnetic metal layer 58 and the insulating layer 59. The first
gap layer 19 may be made of a nonmagnetic insulating material such
as alumina or a nonmagnetic conductive material such as Ru, NiCu,
Ta, W, NiB, or NiP.
The first shield 16A is disposed over the side shields 16C and 16D
and the first gap layer 19, and is in contact with the top surfaces
of the side shields 16C and 16D and the first gap layer 19. In the
medium facing surface 80, part of the first end face portion 16Aa
of the first shield 16A is spaced from the end face of the main
pole 15 by a predetermined distance created by the thickness of the
first gap layer 19. The thickness of the first gap layer 19
preferably falls within the range of 5 to 60 nm, and may be 30 to
60 nm, for example. The end face of the main pole 15 has a side
that is adjacent to the first gap layer 19, and the side defines
the track width.
The second return path section 40 includes magnetic layers 41, 42,
43 and 44. The magnetic layer 41 is disposed on the main pole 15 at
a position away from the medium facing surface 80.
The second portion 20 of the coil includes a first layer 21 and a
second layer 22. As shown in FIG. 4, the first layer 21 is wound
one turn around the magnetic layer 41. The magnetic head further
includes an insulating film 61 made of an insulating material and
interposed between the first layer 21 and each of the first shield
16A, the first gap layer 19 and the magnetic layer 41, and a
nonmagnetic layer 62 made of a nonmagnetic material and disposed
around the first layer 21, the first shield 16A and the magnetic
layer 41. The insulating film 61 and the nonmagnetic layer 62 are
made of alumina, for example. The top surfaces of the first shield
16A, the first layer 21, the magnetic layer 41, the insulating film
61 and the nonmagnetic layer 62 are even with each other.
The magnetic head further includes an insulating layer 63 made of
an insulating material and disposed over the top surfaces of the
first layer 21 and the insulating film 61 and part of the top
surface of the magnetic layer 41. The insulating layer 63 is made
of alumina, for example.
The magnetic layer 42 is disposed on the first shield 16A. The
magnetic layer 43 is disposed on the magnetic layer 41. The
magnetic layer 42 has an end face facing toward the medium facing
surface 80. This end face is located at a distance from the medium
facing surface 80. The distance from the medium facing surface 80
to an arbitrary point on the end face of the magnetic layer 42
increases with increasing distance from the arbitrary point to the
top surface 1a of the substrate 1.
As shown in FIG. 5, the second layer 22 is wound approximately two
turns around the magnetic layer 43. The magnetic head further
includes an insulating film 64 made of an insulating material and
interposed between the second layer 22 and each of the magnetic
layers 42 and 43 and the insulating layer 63, an insulating layer
65 made of an insulating material and disposed in the space between
adjacent turns of the second layer 22, and an insulating layer 66
made of an insulating material and disposed around the second layer
22 and the magnetic layers 42 and 43. The top surfaces of the
second layer 22, the magnetic layers 42 and 43, the insulating film
64 and the insulating layers 65 and 66 are even with each other.
The magnetic head further includes an insulating layer 67 made of
an insulating material and disposed over the top surfaces of the
second layer 22, the insulating film 64 and the insulating layer
65. The insulating film 64 and the insulating layers 65 to 67 are
made of alumina, for example.
The magnetic layer 44 is disposed over the magnetic layers 42 and
43 and the insulating layer 67, and connects the magnetic layer 42
and the magnetic layer 43 to each other. The magnetic layer 44 has
an end face facing toward the medium facing surface 80. This end
face is located at a distance from the medium facing surface 80.
The distance from the medium facing surface 80 to an arbitrary
point on the end face of the magnetic layer 44 increases with
increasing distance from the arbitrary point to the top surface 1a
of the substrate 1.
The magnetic head further includes a protective layer 70 made of a
nonmagnetic material and disposed to cover the write head section
9. The protective layer 70 is made of, for example, an inorganic
insulating material such as alumina.
As has been described, the magnetic head according to the present
embodiment includes the medium facing surface 80, the read head
section 8, and the write head section 9. The medium facing surface
80 faces the recording medium. The read head section 8 and the
write head section 9 are stacked on the substrate 1. The read head
section 8 is located on the rear side in the direction T of travel
of the recording medium (i.e., located on the leading side)
relative to the write head section 9.
The read head section 8 includes: the MR element 5 serving as the
read element; the first read shield layer 3 and the second read
shield layer 7 for shielding the MR element 5, with their
respective portions near the medium facing surface 80 opposed to
each other with the MR element 5 therebetween; the first read
shield gap film 4 disposed between the MR element 5 and the first
read shield layer 3; and the second read shield gap film 6 disposed
between the MR element 5 and the second read shield layer 7.
The write head section 9 includes the coil including the first and
second portions 10 and 20, the main pole 15, the write shield 16,
the gap part 17, the first and second return path sections 30 and
40, and the accommodation part 50. The coil, the main pole 15, the
write shield 16, the gap part 17, the first return path section 30,
the second return path section 40 and the accommodation part 50 are
located above the top surface 1a of the substrate 1. The write
shield 16 includes the first shield 16A, the second shield 16B, and
the two side shields 16C and 16D. The gap part 17 includes the
first gap layer 19 and the second gap layer 18. The first return
path section 30 and the second return path section 40 align along
the direction perpendicular to the top surface 1a of the substrate
1 with the main pole 15 interposed therebetween.
The first return path section 30 includes the magnetic layers 31,
32 and 36. The first return path section 30 is located on the rear
side in the direction T of travel of the recording medium relative
to the main pole 15 and lies between the main pole 15 and the top
surface 1a of the substrate 1. As shown in FIG. 1, the first return
path section 30 connects the write shield 16 and part of the main
pole 15 away from the medium facing surface 80 to each other so
that a first space S1 is defined by the main pole 15, the gap part
17 (the gap layer 18), the write shield 16 and the first return
path section 30 (the magnetic layers 31, 32 and 36).
The accommodation part 50 accommodates at least part of the first
return path section 30. More specifically, the magnetic layers 31
and 32 constituting part of the first return path section 30 are
disposed in the opening 51a of the nonmagnetic layer 51 forming the
accommodation part 50. The magnetic layer 31 includes the
horizontal portion 31A, the first inclined portion 31B and the
second inclined portion 31C. The horizontal portion 31A is located
closer to the top surface 1a of the substrate 1 than is the first
space S1. The first inclined portion 31B is located closer to the
medium facing surface 80 than is the first space S1. The second
inclined portion 31C is located farther from the medium facing
surface 80 than is the first space S1.
The second return path section 40 includes the magnetic layers 41
to 44, and is located on the front side in the direction T of
travel of the recording medium relative to the main pole 15. The
second return path section 40 connects the write shield 16 and part
of the main pole 15 away from the medium facing surface 80 to each
other so that a second space S2 is defined by the main pole 15, the
gap part 17 (the gap layer 19), the write shield 16 and the second
return path section 40 (the magnetic layers 41 to 44).
The first and second portions 10 and 20 of the coil will now be
described in detail with reference to FIG. 3 to FIG. 5. FIG. 3 is a
plan view showing the first portion 10. As previously mentioned,
the first portion 10 is wound approximately three turns around the
second inclined portion 31C and the magnetic layer 32. The first
portion 10 includes three coil elements 10A, 10B and 10C extending
to pass through the first space S1. Note that the coil elements
refer to part of the coil winding. The coil elements 10A, 10B and
10C align in this order in the direction perpendicular to the
medium facing surface 80, the coil element 10A being closest to the
medium facing surface 80. The first portion 10 has a coil
connection part 10E electrically connected to the second portion
20.
FIG. 4 is a plan view showing the first layer 21 of the second
portion 20. As previously mentioned, the first layer 21 is wound
one turn around the magnetic layer 41. The first layer 21 includes
a coil element 21A extending to pass between the first shield 16A
and the magnetic layer 41, in particular, within the second space
S2. The first layer 21 has a coil connection part 21S electrically
connected to the coil connection part 10E of the first portion 10,
and a coil connection part 21E electrically connected to the second
layer 22. The coil connection part 21S is electrically connected to
the coil connection part 10E via a connection layer of columnar
shape (not shown) that penetrates a plurality of layers interposed
between the first layer 21 and the first portion 10. The connection
layer is made of a conductive material such as copper.
FIG. 5 is a plan view showing the second layer 22 of the second
portion 20. As previously mentioned, the second layer 22 is wound
approximately two turns around the magnetic layer 43. The second
layer 22 includes two coil elements 22A and 22B extending to pass
between the magnetic layer 42 and the magnetic layer 43, in
particular, within the second space S2. The coil elements 22A and
22B align in this order in the direction perpendicular to the
medium facing surface 80, the coil element 22A being closer to the
medium facing surface 80. The second layer 22 has a coil connection
part 22S penetrating the insulating layer 63 and the insulating
film 64 and electrically connected to the coil connection part 21E
of the first layer 21. In the example shown in FIG. 3 to FIG. 5,
the first and second portions 10 and 20 are connected in
series.
The coil elements 21A, 22A and 22B extend to pass through the
second space S2. Hereinafter, the coil elements extending to pass
through the first space S1 will also be referred to as the first
coil elements, and the coil elements extending to pass through the
second space S2 will also be referred to as the second coil
elements.
The shape of the main pole 15 will now be described in detail with
reference to FIG. 3 to FIG. 6. As shown in FIG. 3 to FIG. 5, the
main pole 15 includes a track width defining portion 15A and a wide
portion 15B. The track width defining portion 15A has an end face
located in the medium facing surface 80, and an end opposite to the
end face. The wide portion 15B is connected to the end of the track
width defining portion 15A. As shown in FIG. 6, the main pole 15
has: the top surface 15T which is the surface located at the end on
the front side in the direction T of travel of the recording
medium; the bottom end 15L opposite to the top surface 15T; the
first side part; and the second side part. The width of the top
surface 15T in the track width direction TW is greater in the wide
portion 15B than in the track width defining portion 15A.
In the track width defining portion 15A, the width of the top
surface 15T in the track width direction TW is generally constant
regardless of the distance from the medium facing surface 80. In
the wide portion 15B, the width of the top surface 15T in the track
width direction TW is, for example, equal to that in the track
width defining portion 15A when seen at the boundary between the
track width defining portion 15A and the wide portion 15B, and
gradually increases with increasing distance from the medium facing
surface 80, then becoming constant. Here, the length of the track
width defining portion 15A in the direction perpendicular to the
medium facing surface 80 will be referred to as the neck height.
The neck height falls within the range of 0 to 0.3 .mu.m, for
example. A zero neck height means that no track width defining
portion 15A exists and an end face of the wide portion 15B is thus
located in the medium facing surface 80.
The top surface 15T includes a first portion 15T1 and a second
portion 15T2 contiguously arranged in this order, the first portion
15T1 being closer to the medium facing surface 80. The first
portion 15T1 has a first end located in the medium facing surface
80 and a second end opposite to the first end. The second portion
15T2 is connected to the second end of the first portion 15T1.
The bottom end 15L includes a first portion 15L1, a second portion
15L2, a third portion 15L3, and a fourth portion 15L4 contiguously
arranged in this order, the first portion 15L1 being closest to the
medium facing surface 80. The first portion 15L1 has a first end
located in the medium facing surface 80 and a second end opposite
to the first end. The second portion 15L2 is connected to the
second end of the first portion 15L1. The third portion 15L3 has a
third end connected to the second portion 15L2 and a fourth end
that is located farther from the medium facing surface 80 than is
the third end. Each of the first to third portions 15L1 to 15L3 may
be an edge formed by two intersecting planes, or may be a plane
connecting two planes to each other. The fourth portion 15L4 is a
plane connected to the fourth end of the third portion 15L3.
Here, as shown in FIG. 6, assume a first virtual plane P1 and a
second virtual plane P2. The first virtual plane P1 passes through
the first end of the first portion 15T1 of the top surface 15T and
is perpendicular to the medium facing surface 80 and to the
direction T of travel of the recording medium. The second virtual
plane P2 passes through the first end of the first portion 15L1 of
the bottom end 15L and is perpendicular to the medium facing
surface 80 and to the direction T of travel of the recording
medium. The second portion 15T2 of the top surface 15T is
substantially parallel to the first and second virtual planes P1
and P2. The first portion 15T1 is inclined relative to the first
and second virtual planes P1 and P2 and the medium facing surface
80 such that the second end of the first portion 15T1 is located on
the front side in the direction T of travel of the recording medium
relative to the first end of the first portion 15T1.
The first portion 15L1 of the bottom end 15L is inclined relative
to the first and second virtual planes P1 and P2 and the medium
facing surface 80 such that the second end of the first portion
15L1 is located on the rear side in the direction T of travel of
the recording medium relative to the first end of the first portion
15L1. The second and fourth portions 15L2 and 15L4 are
substantially parallel to the first and second virtual planes P1
and P2. The third portion 15L3 is inclined relative to the first
and second virtual planes P1 and P2 and the medium facing surface
80 such that the fourth end of the third portion 15L3 is located on
the rear side in the direction T of travel of the recording medium
relative to the third end of the third portion 15L3.
The first shield 16A of the write shield 16 has the first inclined
surface 16Ab which is the bottom surface. The first inclined
surface 16Ab includes a portion that is opposed to the first
portion 15T1 of the top surface 15T with the first gap layer 19 of
the gap part 17 interposed therebetween. The first inclined surface
16Ab is inclined relative to the first and second virtual planes P1
and P2 and the medium facing surface 80.
The second shield 16B of the write shield 16 includes a portion
interposed between the third portion 15L3 of the bottom end 15L and
the medium facing surface 80. The second shield 16B has the top
surface including the second inclined surface 16Bb. The second
inclined surface 16Bb is inclined relative to the first and second
virtual planes P1 and P2 and the medium facing surface 80.
The top surface of the second shield 16B further includes a flat
portion and a connecting surface. The flat portion is located
farther from the medium facing surface 80 than is the second
inclined surface 16Bb and closer to the top surface 1a of the
substrate 1 than is the second inclined surface 16Bb. The
connecting surface connects the second inclined surface 16Bb and
the flat portion to each other. The flat portion is substantially
parallel to the first and second virtual planes P1 and P2.
Here, as shown in FIG. 6, the length of the first portion 15T1 of
the top surface 15T in the direction perpendicular to the medium
facing surface 80 will be represented by the symbol L.sub.A, the
length of the first portion 15L1 of the bottom end 15L in the
direction perpendicular to the medium facing surface 80 will be
represented by the symbol L.sub.B1, the length of the second
portion 15L2 of the bottom end 15L in the direction perpendicular
to the medium facing surface 80 will be represented by the symbol
L.sub.B2, and the length of the first inclined surface 16Ab in the
direction perpendicular to the medium facing surface 80 will be
represented by the symbol L.sub.C. The length L.sub.A falls within
the range of 0.05 to 0.15 .mu.m, for example. The length L.sub.B1
falls within the range of 0.1 to 0.5 .mu.m, for example. The length
L.sub.B2 falls within the range of 0.2 to 0.6 .mu.m, for example.
The length L.sub.C falls within the range of 0.2 to 0.6 .mu.m, for
example. Note that the neck height can be set to any value
independently of the lengths L.sub.A, L.sub.B1, L.sub.B2 and
L.sub.C mentioned above.
The angle of inclination of the first portion 15T1 of the top
surface 15T relative to the first virtual plane P1 will be
represented by the symbol .theta..sub.T1, and the angle of
inclination of the first portion 15L1 of the bottom end 15L
relative to the second virtual plane P2 will be represented by the
symbol .theta..sub.L1. The angle of inclination .theta..sub.T1
falls within the range of 22.degree. to 35.degree., for example.
The angle of inclination .theta..sub.L1 falls within the range of
30.degree. to 50.degree., for example.
Assume also a virtual plane P3 that passes through the third end of
the third portion 15L3 of the bottom end 15L and is parallel to the
first and second virtual planes P1 and P2. The angle of inclination
of the third portion 15L3 relative to the virtual plane P3 will be
represented by the symbol .theta..sub.L3. The angle of inclination
.theta..sub.L3 falls within the range of 22.degree. to 60.degree.,
for example.
The thickness of the main pole 15 in the medium facing surface 80,
i.e., the distance between the first virtual plane P1 and the
second virtual plane P2, will be represented by the symbol D0. The
distance between the second portion 15T2 of the top surface 15T and
the first virtual plane P1 will be represented by the symbol D1.
The distance between the second portion 15L2 of the bottom end 15L
and the second virtual plane P2 will be represented by the symbol
D2. The distance between the fourth portion 15L4 and the virtual
plane P3 will be represented by the symbol D3. The distance D0
falls within the range of 0.05 to 0.1 .mu.m, for example. The
distance D1 falls within the range of 0.02 to 0.1 .mu.m, for
example. The distance D2 falls within the range of 0.1 to 0.5
.mu.m, for example. The distance D3 falls within the range of 0.1
to 0.5 .mu.m, for example.
The end face of the main pole 15 located in the medium facing
surface 80 has a first side adjacent to the first gap layer 19, a
second side connected to one end of the first side, and a third
side connected to the other end of the first side. The first side
defines the track width. The position of an end of a record bit to
be recorded on the recording medium depends on the position of the
first side. The end face of the main pole 15 located in the medium
facing surface 80 decreases in width in the track width direction
TW with increasing distance from the first side, that is, with
increasing distance from the first virtual plane P1. Each of the
second side and the third side forms an angle of, for example,
7.degree. to 17.degree., or preferably 10.degree. to 15.degree.,
relative to a direction perpendicular to the first virtual plane
P1. The first side has a length in the range of 0.05 to 0.20 .mu.m,
for example.
The function and effects of the magnetic head according to the
present embodiment will now be described. The magnetic head writes
data on the recording medium by using the write head section 9 and
reads data stored on the recording medium by using the read head
section 8. In the write head section 9, the coil including the
first and second portions 10 and 20 produces magnetic fields
corresponding to data to be written on the recording medium. A
magnetic flux corresponding to the magnetic field produced by the
first portion 10 passes through the first return path section 30
and the main pole 15. A magnetic flux corresponding to the magnetic
field produced by the second portion 20 passes through the second
return path section 40 and the main pole 15. Consequently, the main
pole 15 allows the magnetic flux corresponding to the magnetic
field produced by the first portion 10 and the magnetic flux
corresponding to the magnetic field produced by the second portion
20 to pass.
The first and second portions 10 and 20 may be connected in series
or in parallel. In either case, the first and second portions 10
and 20 are connected such that the magnetic flux corresponding to
the magnetic field produced by the first portion 10 and the
magnetic flux corresponding to the magnetic field produced by the
second portion 20 flow in the same direction through the main pole
15.
The main pole 15 allows the magnetic fluxes corresponding to the
magnetic fields produced by the coil to pass as mentioned above,
and produces a write magnetic field for writing data on the
recording medium by means of the perpendicular magnetic recording
system.
The write shield 16 captures a disturbance magnetic field applied
to the magnetic head from the outside thereof. This makes it
possible to prevent erroneous writing on the recording medium
induced by the disturbance magnetic field intensively captured into
the main pole 15. The write shield 16 also has the function of
capturing a magnetic flux produced from the end face of the main
pole 15 and spreading in directions other than the direction
perpendicular to the plane of the recording medium, so as to
prevent the magnetic flux from reaching the recording medium.
Furthermore, the write shield 16 and the first and second return
path sections 30 and 40 have the function of allowing a magnetic
flux that has been produced from the end face of the main pole 15
and has magnetized the recording medium to flow back. More
specifically, a part of the magnetic flux that has been produced
from the end face of the main pole 15 and has magnetized the
recording medium flows back to the main pole 15 through the write
shield 16 and the first return path section 30. Another part of the
magnetic flux that has been produced from the end face of the main
pole 15 and has magnetized the recording medium flows back to the
main pole 15 through the write shield 16 and the second return path
section 40.
The write shield 16 includes the first shield 16A, the second
shield 16B, and the two side shields 16C and 16D. The present
embodiment thus makes it possible that, in regions on both the rear
side and the front side in the direction T of travel of the
recording medium relative to the end face of the main pole 15 and
regions on opposite sides of the end face of the main pole 15 in
the track width direction TW, a magnetic flux that is produced from
the end face of the main pole 15 and spreads in directions other
than the direction perpendicular to the plane of the recording
medium can be captured and thereby prevented from reaching the
recording medium. Consequently, the present embodiment makes it
possible to prevent adjacent track erasure induced by a skew. The
first and second shields 16A and 16B contribute not only to the
prevention of adjacent track erasure induced by a skew but also to
an increase in the gradient of the write magnetic field. The side
shields 16C and 16D greatly contribute to the prevention of
adjacent track erasure, in particular. According to the present
embodiment, such functions of the write shield 16 serve to increase
the recording density.
Furthermore, as shown in FIG. 2, the present embodiment is
configured so that in the medium facing surface 80, the distance
between the first and second side parts of the main pole 15 in the
track width direction TW, i.e., the width of the end face of the
main pole 15, decreases with increasing distance from the first
virtual plane P1. According to the present embodiment, this feature
also serves to prevent adjacent track erasure induced by a
skew.
The present embodiment is also configured so that in the medium
facing surface 80, the distance between the first and second
sidewalls of the side shields 16C and 16D in the track width
direction TW decreases with increasing distance from the first
virtual plane P1, as does the distance between the first and second
side parts of the main pole 15. The present embodiment thus allows
both the distance between the first side part and the first
sidewall and the distance between the second side part and the
second sidewall to be small and constant in the medium facing
surface 80. This configuration allows the side shields 16C and 16D
to efficiently capture the magnetic flux that is produced from the
end face of the main pole 15 and spreads out to opposite areas in
the track width direction TW. Consequently, according to the
present embodiment, it is possible to enhance the function of the
side shields 16C and 16D in particular, and to thereby enable more
effective prevention of adjacent track erasure induced by a
skew.
The write shield 16 cannot capture much magnetic flux if the write
shield 16 is not magnetically connected with any magnetic layer
having a sufficiently large volume enough to accommodate the
magnetic flux captured by the write shield 16. In the present
embodiment, there are provided the first return path section 30
(the magnetic layers 31, 32 and 36) which magnetically couples the
second shield 16B of the write shield 16 and the main pole 15 to
each other, and the second return path section 40 (the magnetic
layers 41 to 44) which magnetically couples the first shield 16A of
the write shield 16 and the main pole 15 to each other. Such a
configuration allows the magnetic flux captured by the write shield
16 to flow into the main pole 15 by way of the first and second
return path sections 30 and 40. In the present embodiment, the
first and second return path sections 30 and 40 and the main pole
15, which are magnetic layers large in volume, are magnetically
connected to the write shield 16. This allows the write shield 16
to capture much magnetic flux, so that the above-described effect
of the write shield 16 can be exerted effectively.
If the first return path section has an end face that is exposed
over a large area in the medium facing surface 80, part of the
magnetic flux that has been captured from the end face of the write
shield 16 into the write shield 16 and has reached the first return
path section may leak from the end face of the first return path
section toward the recording medium. This may result in the
occurrence of adjacent track erasure. Furthermore, heat generated
by the first portion 10 of the coil may cause expansion of part of
the first return path section and thereby cause the end face of the
first return path section which constitutes part of the medium
facing surface 80 to protrude toward the recording medium. As a
result, the end face of the main pole 15 and an end of the read
head section 8 located in the medium facing surface 80 may get
farther from the recording medium. This may result in degradation
of the read and write characteristics.
In contrast to this, in the present embodiment, the first return
path section 30 does not have an end face that is exposed over a
large area in the medium facing surface 80. More specifically, in
the present embodiment, the magnetic layers 31 and 32 constituting
part of the first return path section 30 are accommodated in the
accommodation part 50. The accommodation part 50 includes the
interposer 50A interposed between the first return path section 30
and the medium facing surface 80. The interposer 50A has the
inclined surface 50Aa facing toward the first return path section
30, and the first return path section 30 includes the first
inclined portion 31B extending along the inclined surface 50Aa.
These features of the present embodiment make it possible to
connect the first return path section 30 to the write shield 16
without causing the end face of the first return path section 30 to
be exposed over a large area in the medium facing surface 80.
Consequently, according to the present embodiment, it is possible
to avoid the above-described problems resulting from the
configuration in which the end face of the first return path
section is exposed over a large area in the medium facing surface
80. More specifically, the present embodiment makes it possible to
suppress the leakage of magnetic flux from the first return path
section 30 toward the recording medium and suppress the protrusion
of part of the medium facing surface 80 in the vicinity of the
first inclined portion 31B.
In the present embodiment, the interposer 50A, which is composed of
part of the nonmagnetic layer 51 and part of the nonmagnetic film
52, is made of an inorganic insulating material harder than the
material of the first inclined portion 31B, in particular. The
interposer 50A therefore has the function of suppressing a change
in the position of the surface of the first inclined portion 31B
facing toward the interposer 50A. Consequently, according to the
present embodiment, it is possible to more effectively suppress the
protrusion of part of the medium facing surface 80 in the vicinity
of the first inclined portion 31B.
Reference is now made to FIG. 7A and FIG. 7B to describe the
effects resulting from the configuration in which the interposer
50A of the accommodation part 50 has the inclined surface 50Aa.
FIG. 7A and FIG. 7B are explanatory diagrams illustrating the
function of the interposer 50A of the accommodation part 50. The
difference between FIG. 7A and FIG. 7B will be described later. In
FIG. 7A and FIG. 7B, the direction perpendicular to the top surface
1a of the substrate 1 is indicated by a dot-and-dash line, and a
first angle formed by the inclined surface 50Aa relative to the
direction perpendicular to the top surface 1a of the substrate 1 is
represented by the symbol .theta.1. When heat is generated by the
first portion 10 of the coil, the first portion 10 and components
therearound are heated and thereby expanded. This causes an
external force to be applied to the first inclined portion 31B in
the direction from the first portion 10 to the medium facing
surface 80. In FIG. 7A and FIG. 7B, the arrow with reference
numeral 91 indicates the aforementioned external force applied to
the first inclined portion 31B. This external force 91 can be
decomposed into a component 91a perpendicular to the inclined
surface 50Aa and a component 91b in the direction parallel to the
inclined surface 50Aa and toward the second shield 16B. As
previously mentioned, the interposer 50A has the function of
suppressing a change in the position of the surface of the first
inclined portion 31B facing toward the interposer 50A. Therefore,
the aforementioned component 91b deforms the first inclined portion
31B such that the second end face 31Bb shifts in the direction of
the component 91b.
The heat generated by the first portion 10 of the coil also heats
and expands the first inclined portion 31B. This also deforms the
first inclined portion 31B such that the second end face 31Bb
shifts in the direction of the component 91b.
Consequently, an external force 92 is applied to the second shield
16B from the second end face 31Bb in a direction the same as the
direction of the aforementioned component 91b. This external force
92 can be decomposed into a component 92a perpendicular to the
second end face 31Bb and a component 92b in the direction parallel
to the second end face 31Bb and toward the medium facing surface
80. The aforementioned component 92b deforms the second shield 16B
such that the second end face portion 16Ba protrudes toward the
recording medium. Such a deformation of the second shield 16B
causes the main pole 15 located near the second shield 16B to be
also deformed such that its end face protrudes toward the recording
medium. According to the present embodiment, it is thus possible to
bring the end face of the main pole 15 near the recording medium
while suppressing the protrusion of part of the medium facing
surface 80 in the vicinity of the first inclined portion 31B. This
allows the improvement of write characteristics. The first angle
.theta.1 is preferably in the range of 5.degree. to 45.degree., and
more preferably in the range of 8.degree. to 16.degree..
If the inclined surface 50Aa is replaced with a wall face parallel
to the medium facing surface 80 and the first inclined portion 31B
is replaced with a portion of the magnetic layer 31 extending in
the direction perpendicular to the top surface 1a of the substrate
1, the aforementioned component 92b will not occur on the second
shield 16B and therefore it is not possible to bring the end face
of the main pole 15 near the recording medium in the
above-described manner.
In the present embodiment, as shown in FIG. 7A and FIG. 7B, the
first end face 31Ba of the inclined portion 31B has an end 31Ba1
located in the medium facing surface 80. When seen at this end
31Ba1, the first end face 31Ba forms a second angle .theta.2
greater than 90.degree. relative to a part of the medium facing
surface 80, the part of the medium facing surface 80 being located
on the front side in the direction of travel of the recording
medium relative to the end 31Ba1. The second angle .theta.2 may be
equal to 180.degree. minus the first angle .theta.1, or may be
smaller than 180.degree. minus the first angle .theta.1.
FIG. 7A shows the case where the second angle .theta.2 is equal to
180.degree. minus the first angle .theta.1. In FIG. 7A, the angle
formed by the first end face 31Ba relative to the direction
perpendicular to the top surface 1a of the substrate 1 is equal to
the first angle .theta.1 regardless of position on the first end
face 31Ba. When the second angle .theta.2 is equal to 180.degree.
minus the first angle .theta.1, the second angle .theta.2
preferably falls within the range of 135.degree. to 175.degree.,
and more preferably within the range of 164.degree. to
172.degree..
FIG. 7B shows the case where the second angle .theta.2 is smaller
than 180.degree. minus the first angle .theta.1. In FIG. 7B, a
portion of the first end face 31Ba located in the vicinity of the
end 31Ba1 forms an angle greater than the first angle .theta.1
relative to the direction perpendicular to the top surface 1a of
the substrate 1. The remaining portion of the first end face 31Ba
forms an angle equal to the first angle .theta.1 relative to the
direction perpendicular to the top surface 1a of the substrate 1.
When the second angle .theta.2 is smaller than 180.degree. minus
the first angle .theta.1, the second angle .theta.2 preferably
falls within the range of 120.degree. to 175.degree., and more
preferably within the range of 135.degree. to 172.degree..
A description will now be given of the effect provided by the
feature that the second angle .theta.2 is greater than 90.degree..
If the magnetic path formed by the write shield 16 and the first
return path section 30 has an edge with an angle of 90.degree. or
less in the vicinity of the medium facing surface 80, there tends
to be magnetic field leakage from the vicinity of this edge to the
outside of the magnetic path. As a result, adjacent track erasure
may occur. In contrast to this, in the present embodiment, since
the second angle .theta.2 is greater than 90.degree., the magnetic
path formed by the write shield 16 and the first return path
section 30 does not have an edge with an angle of 90.degree. or
less in the vicinity of the medium facing surface 80. According to
the present embodiment, it is thus possible to prevent the
occurrence of adjacent track erasure induced by an edge with an
angle of 90.degree. or less.
The features of the shape of the main pole 15 and the effects
resulting therefrom will now be described. In the present
embodiment, the top surface 15T of the main pole 15 includes the
first portion 15T1 inclined relative to the first and second
virtual planes P1 and P2 and the medium facing surface 80, while
the bottom end 15L of the main pole 15 includes the first and third
portions 15L1 and 15L3 inclined relative to the first and second
virtual planes P1 and P2 and the medium facing surface 80. This
allows the main pole 15 to have a small thickness in the medium
facing surface 80, thereby allowing the prevention of adjacent
track erasure induced by a skew. On the other hand, since a portion
of the main pole 15 away from the medium facing surface 80 can have
a large thickness, it is possible for the main pole 15 to direct
much magnetic flux to the medium facing surface 80, and this allows
the improvement of write characteristics such as the overwrite
property.
Furthermore, in the present embodiment, the bottom end 15L of the
main pole 15 includes the second portion 15L2. This allows the
distance between the third portion 15L3 and the second shield 16B
to be greater than that in the case without the second portion
15L2. The present embodiment thus makes it possible to prevent
degradation in the write characteristics induced by magnetic flux
leakage from the main pole 15 to the write shield 16.
According to the present embodiment, the above-described features
of the shape of the main pole 15 make it possible to prevent the
skew-induced problems and provide improved write
characteristics.
A method of manufacturing the magnetic head according to the
present embodiment will now be described with reference to FIG. 8A
through FIG. 24B. FIG. 8A through FIG. 24B each show a stack of
layers formed in the process of manufacturing the magnetic head.
FIG. 8A to FIG. 24A each show a cross section perpendicular to the
medium facing surface 80 and to the top surface 1a of the substrate
1, or the main cross section, in particular. FIG. 8B to FIG. 16B
each show a cross section parallel to the position at which the
medium facing surface 80 is to be formed. In FIG. 8A to FIG. 16A,
lines nB-nB (n is any integer between 8 and 16 inclusive) indicate
the positions of the cross sections shown in FIG. 8B to FIG. 16B.
FIG. 17B to FIG. 24B each show a cross section taken at the
position at which the medium facing surface 80 is to be formed. The
symbol "ABS" in FIG. 8A to FIG. 24A indicates the position at which
the medium facing surface 80 is to be formed.
In the method of manufacturing the magnetic head according to the
present embodiment, first, as shown in FIG. 8A and FIG. 8B, the
insulating layer 2, the first read shield layer 3 and the first
read shield gap film 4 are formed in this order on the substrate 1.
Next, the MR element 5 and not-shown leads connected to the MR
element 5 are formed on the first read shield gap film 4. The MR
element 5 and the leads are then covered with the second read
shield gap film 6. Then, the second read shield layer 7, the
nonmagnetic layer 71 and the middle shield layer 72 are formed in
this order on the second read shield gap film 6.
FIG. 9A and FIG. 9B show the next step. In this step, the
nonmagnetic layer 51 is formed over the entire top surface of the
stack. The nonmagnetic layer 51 has a thickness in the range of 1.0
to 1.6 .mu.m, for example.
FIG. 10A and FIG. 10B show the next step. In this step, first, an
etching mask material layer made of, for example, Ru, is formed on
the top surface of the nonmagnetic layer 51. The etching mask
material layer has a thickness in the range of 50 to 60 nm, for
example. Next, a photoresist mask 82 having an opening 82a is
formed on the etching mask material layer. The opening 82a is
shaped to correspond to the planar shape of the opening 51a which
is to be formed later in the nonmagnetic layer 51. The photoresist
mask 82 is formed by patterning a photoresist layer. Note that any
photoresist mask to be employed in any subsequent step is formed in
the same manner as the photoresist mask 82. Then, a portion of the
etching mask material layer exposed from the opening 82a of the
photoresist mask 82 is removed by, for example, ion beam etching
(hereinafter referred to as IBE) using the photoresist mask 82 as
the etching mask. This makes the etching mask material layer into
an etching mask 81. The etching mask 81 has an opening 81a shaped
to correspond to the planar shape of the opening 51a to be formed
later in the nonmagnetic layer 51.
Then, using the etching mask 81 and the photoresist mask 82 as an
etching mask, the nonmagnetic layer 51 is taper-etched by, for
example, reactive ion etching (hereinafter referred to as RIE) to
form the opening 51a in the nonmagnetic layer 51. The middle shield
layer 72 functions as an etching stopper for stopping the etching
when the nonmagnetic layer 51 is etched by RIE. The etching mask 81
and the photoresist mask 82 are then removed.
Where the nonmagnetic layer 51 is formed of alumina, an etching gas
containing BCl.sub.3 and N.sub.2, for example, is used for RIE to
taper-etch the nonmagnetic layer 51 in the aforementioned etching
step. BCl.sub.3 is a main component contributing to the etching of
the nonmagnetic layer 51. N.sub.2 is a gas for forming, during the
etching of the nonmagnetic layer 51, a sidewall-protecting film on
the sidewall of the groove formed by the etching. The etching gas
containing N.sub.2 serves to form the sidewall-protecting film on
the sidewall of the groove during the etching of the nonmagnetic
layer 51, thereby serving to make the first and second wall faces
of the opening 51a inclined relative to the direction perpendicular
to the top surface 1a of the substrate 1. The first and second wall
faces of the opening 51a form an angle in the range of, for
example, 5.degree. to 45.degree. relative to the direction
perpendicular to the top surface 1a of the substrate 1.
FIG. 11A and FIG. 11B show the next step. In this step, first, the
nonmagnetic film 52 is formed over the entire top surface of the
stack. Where alumina is selected as the material of the nonmagnetic
film 52, the nonmagnetic film 52 is formed by atomic layer
deposition (hereinafter referred to as ALD), for example. The
nonmagnetic film 52 has a thickness in the range of 0.1 to 0.2
.mu.m, for example. Next, the electrode film 73 is formed over the
entire top surface of the stack by sputtering or ion beam
deposition, for example. Then, a preliminary magnetic layer 31P,
which is to later become the magnetic layer 31, is formed by frame
plating using the electrode film 73 as an electrode and seed layer.
The preliminary magnetic layer 31P has a thickness in the range of
0.4 to 0.6 .mu.m, for example. Part of the preliminary magnetic
layer 31P is located above the top surface of the nonmagnetic layer
51.
The preliminary magnetic layer 31P includes the horizontal portion
31A, the first inclined portion 31B and the second inclined portion
31C. The horizontal portion 31A, the first inclined portion 31B and
the second inclined portion 31C are thus formed from the same
material simultaneously in the step of forming the preliminary
magnetic layer 31P.
FIG. 12A and FIG. 12B show the next step. In this step, a
preliminary magnetic layer 32P, which is to later become the
magnetic layer 32, is formed on the preliminary magnetic layer 31P
by frame plating using the electrode film 73 as an electrode and
seed layer. The preliminary magnetic layer 32P is formed such that
its top surface is higher in level than the part of the preliminary
magnetic layer 31P located above the top surface of the nonmagnetic
layer 51.
FIG. 13A and FIG. 13B show the next step. In this step, first, the
insulating film 53 is formed over the entire top surface of the
stack. Where alumina is selected as the material of the insulating
film 53, the insulating film 53 is formed by ALD, for example. The
insulating film 53 has a thickness in the range of 0.1 to 0.2
.mu.m, for example.
Next, a conductive layer 10P is formed. The conductive layer 10P is
to later become the first portion 10 of the coil. The conductive
layer 10P is formed in the following manner, for example. First, a
seed layer to become a part of the conductive layer 10P is formed.
Then, a plating film to become another part of the conductive layer
10P is formed on the seed layer by frame plating, for example. The
plating film has a planar spiral shape like that of the first
portion 10. The outermost turn of the plating film is formed such
that a part thereof lies over a part of the insulating film 53 that
is located above the top surface of the nonmagnetic layer 51. The
innermost turn of the plating film is formed such that a part
thereof lies over a part of the insulating film 53 that is located
above the top surface of the preliminary magnetic layer 32P. Then,
part of the seed layer other than the part lying under the plating
film is removed by, for example, IBE, using the plating film as the
etching mask.
FIG. 14A and FIG. 14B show the next step. In this step, the
insulating layer 54 is formed to fill the space between adjacent
turns of the conductive layer 10P and cover the conductive layer
10P. Where alumina is selected as the material of the insulating
layer 54, the insulating layer 54 is formed by ALD, for example.
The insulating layer 54 has a thickness in the range of 0.3 to 0.5
.mu.m, for example.
FIG. 15A and FIG. 15B show the next step. In this step, the
conductive layer 10P, the preliminary magnetic layers 31P and 32P,
the insulating film 53 and the insulating layer 54 are polished by,
for example, chemical mechanical polishing (hereinafter referred to
as CMP), until the electrode film 73 is exposed. In this polishing
process, the electrode film 73 functions as a polishing stopper for
stopping the polishing. As a result of this polishing process, the
conductive layer 10P becomes the first portion 10 and the
preliminary magnetic layers 31P and 32P become the magnetic layers
31 and 32, respectively.
FIG. 16A and FIG. 16B show the next step. In this step, first, the
insulating layer 55 is formed over the first portion 10, the
insulating film 53 and the insulating layer 54. Then, a magnetic
layer 16BP, which is to later become the second shield 16B, is
formed over the first inclined portion 31B of the magnetic layer 31
and the electrode film 73, and the magnetic layer 36 is formed over
the second inclined portion 31C of the magnetic layer 31 and the
magnetic layer 32, by employing, for example, frame plating with
the electrode film 73 used as an electrode.
FIG. 17A and FIG. 17B show the next step. In this step, first, part
of the magnetic layer 16BP is etched by, for example, IBE. This
etching is performed to determine the length of the second inclined
surface 16Bb of the second shield 16B, which is to be formed later,
in the direction perpendicular to the medium facing surface 80.
Next, the nonmagnetic layer 56 is formed over the entire top
surface of the stack. The nonmagnetic layer 56 is then polished by,
for example, CMP, until the magnetic layers 16BP and 36 are
exposed.
FIG. 18A and FIG. 18B show the next step. In this step, first, part
of the magnetic layer 16BP and part of the magnetic layer 36 are
etched by, for example, IBE, so as to provide the magnetic layer
16BP with the second inclined surface 16Bb and to chamfer corners
at the edge of the top surface of the magnetic layer 36. This makes
the magnetic layer 16BP into the second shield 16B. Next, a
not-shown photoresist mask is formed to cover the second shield 16B
and the magnetic layer 36. Using this photoresist mask as an
etching mask, the nonmagnetic layer 56 is then taper-etched by, for
example, RIE. Where the nonmagnetic layer 56 is made of alumina,
the etching conditions for the nonmagnetic layer 56 may be the same
as those for the nonmagnetic layer 51. The photoresist mask is then
removed. The step shown in FIG. 18A and FIG. 18B determines the
shape of the bottom end 15L of the main pole 15.
FIG. 19A and FIG. 19B show the next step. In this step, first, the
side shields 16C and 16D are formed on the second shield 16B by,
for example, frame plating using the electrode film 73 as an
electrode. Next, the second gap layer 18 is formed to cover the
second shield 16B and the side shields 16C and 16D. Where alumina
is selected as the material of the second gap layer 18, the second
gap layer 18 is formed by ALD, for example. Where Ru is selected as
the material of the second gap layer 18, the second gap layer 18 is
formed by chemical vapor deposition, for example. Next, the second
gap layer 18 is selectively etched to form therein an opening for
exposing the top surface of the magnetic layer 36 and an opening
for exposing the coil connection part 10E (see FIG. 3) of the first
portion 10 of the coil. Next, a magnetic layer 15P, which is to
later become the main pole 15, and a not-shown connection layer are
formed by frame plating, for example. The magnetic layer 15P and
the connection layer are formed such that their top surfaces are
higher in level than the portions of the second gap layer 18 lying
on the side shields 16C and 16D.
FIG. 20A and FIG. 20B show the next step. In this step, first, the
nonmagnetic layer 57 is formed over the entire top surface of the
stack. The nonmagnetic layer 57 is then polished by, for example,
CMP, until the magnetic layer 15P and the connection layer are
exposed. Next, the nonmagnetic metal layer 58 and the insulating
layer 59 are formed on the magnetic layer 15P. A photoresist mask
83 is then formed over the nonmagnetic layer 57, the nonmagnetic
metal layer 58 and the insulating layer 59. Portions of the
magnetic layer 15P, the side shields 16C and 16D and the second gap
layer 18 are then etched by, for example, IBE, using the
nonmagnetic metal layer 58, the insulating layer 59 and the
photoresist mask 83 as an etching mask. This makes the magnetic
layer 15P into the main pole 15. The photoresist mask 83 is then
removed.
Where IBE is employed to etch the portions of the magnetic layer
15P, the side shields 16C and 16D and the second gap layer 18, the
etching is performed such that ion beams travel in a direction at
an angle of 40.degree. to 75.degree. relative to the direction
perpendicular to the top surface 1a of the substrate 1 and that the
direction of travel of the ion beams is caused to rotate as viewed
in the direction perpendicular to the top surface 1a of the
substrate 1. The arrows in FIG. 20A indicate the direction of
travel of the ion beams. Performing IBE in such a manner provides
the magnetic layer 15P with a top surface having the first portion
15T1 and the second portion 15T2.
FIG. 21A and FIG. 21B show the next step. In this step, first, the
first gap layer 19 is formed over the entire top surface of the
stack by sputtering or chemical vapor deposition, for example. The
first gap layer 19, the nonmagnetic metal layer 58, and the
insulating layer 59 are then selectively etched by, for example,
IBE, so that part of the top surface 15T of the main pole 15, part
of each of the top surfaces of the side shields 16C and 16D, and
the top surface of the connection layer are exposed. Frame plating,
for example, is then performed to form the first shield 16A over
the side shields 16C and 16D and the first gap layer 19 and form
the magnetic layer 41 on the main pole 15.
Next, the insulating film 61 is formed over the entire top surface
of the stack. The insulating film 61 is then selectively etched by,
for example, IBE, so that the top surface of the connection layer
is exposed. The first layer 21 of the second portion 20 of the coil
is then formed by frame plating, for example. The first layer 21 is
formed such that its top surface is higher in level than portions
of the insulating film 61 lying on the first shield 16A and the
magnetic layer 41. Next, the nonmagnetic layer 62 is formed over
the entire top surface of the stack. The first layer 21, the
insulating film 61 and, the nonmagnetic layer 62 are then polished
by, for example, CMP, until the first shield 16A and the magnetic
layer 41 are exposed.
FIG. 22A and FIG. 22B show the next step. In this step, first, the
insulating layer 63 is formed over the entire top surface of the
stack. The insulating layer 63 is then selectively etched by, for
example, IBE, so that the top surfaces of the first shield 16A and
the magnetic layer 41 are exposed. Then, the magnetic layer 42 is
formed on the first shield 16A and the magnetic layer 43 is formed
on the magnetic layer 41 by performing frame plating, for
example.
Next, the insulating film 64 is formed over the entire top surface
of the stack. The insulating layer 63 and the insulating film 64
are then selectively etched by, for example, IBE, so that the coil
connection part 21E (see FIG. 4) of the first layer 21 is exposed.
Next, the second layer 22 of the second portion 20 of the coil and
the insulating layer 65 are formed. The methods for forming the
second layer 22 and the insulating layer 65 are the same as the
those for forming the conductive layer 10P and the insulating layer
54. Next, the insulating layer 66 is formed over the entire top
surface of the stack. The second layer 22, the insulating layers 65
and 66 and the insulating film 64 are then polished by, for
example, CMP, until the top surfaces of the magnetic layers 43 and
43 are exposed.
Next, the insulating layer 67 is formed over the second layer 22,
the insulating film 64 and the insulating layer 65. The magnetic
layer 44 is then formed over he magnetic layers 42 and 43 and the
insulating layer 67 by frame plating, for example.
FIG. 23A and FIG. 23B show the next step. In this step, first, a
photoresist mask 84 is formed on the top surface of the stack. The
photoresist mask 84 is not present in the position ABS at which the
medium facing surface 80 is to be formed, but is present on a
portion of the stack that is to remain as the magnetic head (the
portion located on the right side relative to the position ABS in
FIG. 23A) and covers part of the magnetic layer 44. The photoresist
mask 84 has an end closest to the position ABS. The distance from
this end to the position ABS falls within the range of 0.2 to 0.5
.mu.m, for example.
Using the photoresist mask 84 as an etching mask, the first shield
16A and the magnetic layers 42 and 44 are then etched by IBE, for
example. This provides the magnetic layers 42 and 44 with
respective end faces facing toward the medium facing surface 80.
Furthermore, the first shield 16A is provided with an inclined
surface intersecting the position ABS. This inclined surface is to
become the connecting surface 16Ad (see FIG. 6) later. The
respective end faces of the magnetic layers 42 and 44 and the
inclined surface of the first shield 16A formed in this way are
contiguous with each other to form one plane. This plane is at an
angle of, for example, 10.degree. to 15.degree. relative to the
direction perpendicular to the top surface 1a of the substrate 1.
The photoresist mask 84 is then removed.
FIG. 24A and FIG. 24B show the next step. In this step, first, the
protective layer 70 is formed to cover the entire top surface of
the stack. Wiring, terminals and other components are then formed
on the protective layer 70, and the substrate 1 is cut near the
position ABS at which the medium facing surface 80 is to be formed.
The cut surface is polished into the medium facing surface 80, and
then fabrication of flying rails and other processes are performed
to complete the magnetic head.
As described above, the method of manufacturing the magnetic head
according to the present embodiment includes the steps of forming
the accommodation part 50 (the nonmagnetic layer 51 and the
nonmagnetic film 52); forming the first return path section 30 (the
magnetic layers 31, 32 and 36) after the accommodation part 50 is
formed; and forming the coil, the main pole 15, the write shield
16, and the gap part 17 (the first gap layer 19 and the second gap
layer 18) after the first return path section 30 is formed. In the
present embodiment, the step of forming the first return path
section 30 forms the horizontal portion 31A, the first inclined
portion 31B and the second inclined portion 31C of the magnetic
layer 31 from the same material simultaneously. The present
embodiment thus allows the first return path section 30 to be
formed in a smaller number of steps than in the case of forming the
horizontal portion 31A, the first inclined portion 31B and the
second inclined portion 31C of the magnetic layer 31
separately.
Second Embodiment
A magnetic head according to a second embodiment of the invention
will now be described with reference to FIG. 25 and FIG. 26. FIG.
25 is a plan view showing a plurality of first coil elements of the
coil of the magnetic head according to the present embodiment. FIG.
26 is a plan view showing a plurality of second coil elements of
the coil of the magnetic head according to the present
embodiment.
The configuration of the magnetic head according to the present
embodiment is different from that of the magnetic head according to
the first embodiment in the following respects. In the magnetic
head according to the present embodiment, the coil is wound
approximately three turns around the main pole 15. The coil of the
present embodiment has three line-shaped portions 11, 12 and 13
shown in FIG. 25 in place of the first portion 10 of the first
embodiment shown in FIG. 3. The coil of the present embodiment
further has a first layer 21 shaped as shown in FIG. 26, in place
of the first layer 21 of the first embodiment shown in FIG. 4. The
coil of the present embodiment further has two line-shaped portions
221 and 222 shown in FIG. 26 in place of the second layer 22 of the
first embodiment shown in FIG. 5.
As shown in FIG. 25, the line-shaped portions 11, 12 and 13
respectively include first coil elements 11A, 12B and 13C extending
to pass through the first space S1. The first coil elements 11A,
12B and 13C align in this order in the direction perpendicular to
the medium facing surface 80, the coil element 11A being closest to
the medium facing surface 80.
As shown in FIG. 26, the first layer 21 of the present embodiment
includes a second coil element 21A extending to pass through the
second space S2. The coil element 21A passes between the first
shield 16A and the magnetic layer 41, in particular. As shown in
FIG. 26, the line-shaped portions 221 and 222 respectively include
second coil elements 221A and 222B extending to pass through the
second space S2. The second coil elements 221A and 222B align in
this order in the direction perpendicular to the medium facing
surface 80, the coil element 221A being closer to the medium facing
surface 80. The coil elements 221A and 222B pass between the
magnetic layer 42 and the magnetic layer 43, in particular.
The line-shaped portions 11, 12 and 13 are electrically connected
to the first layer 21 and the line-shaped portions 221 and 222 via
five connection layers 90 of columnar shape, which penetrate a
plurality of layers interposed therebetween, so as to form a coil
that is wound helically around the main pole 15.
The remainder of the configuration, function and effects of the
present embodiment are similar to those of the first
embodiment.
Third Embodiment
A magnetic head according to a third embodiment of the invention
will now be described with reference to FIG. 27. FIG. 27 is a
cross-sectional view of the magnetic head according to the present
embodiment. Note that FIG. 27 shows a cross section perpendicular
to the medium facing surface and to the top surface of the
substrate, or the main cross section, in particular. The magnetic
head according to the present embodiment is without the magnetic
layer 32. The opening 51a of the nonmagnetic layer 51 constituting
the accommodation part 50 and the horizontal portion 31A of the
magnetic layer 31 are smaller in size by an amount corresponding to
the magnetic layer 32 which is absent. The top end of the second
inclined portion 31C of the magnetic layer 31 is connected to the
vicinity of the end of the bottom surface of the magnetic layer 36
closest to the medium facing surface 80.
The coil of the present embodiment may be configured to be
helically wound around the main pole 15 as in the second
embodiment. The remainder of the configuration, function and
effects of the present embodiment are similar to those of the first
or second embodiment.
Fourth Embodiment
A magnetic head according to a fourth embodiment of the invention
will now be described with reference to FIG. 28 and FIG. 29. FIG.
28 is a cross-sectional view of the magnetic head according to the
present embodiment. Note that FIG. 28 shows a cross section
perpendicular to the medium facing surface and to the top surface
of the substrate, or the main cross section, in particular. FIG. 29
is a plan view showing a second layer of the second portion of the
coil of the magnetic head according to the present embodiment.
The configuration of the magnetic head according to the present
embodiment is different from that of the magnetic head according to
the first embodiment in the following respects. The second portion
20 of the coil of the present embodiment includes a second layer
122 in place of the second layer 22 of the first embodiment. As
shown in FIG. 29, the second layer 122 is wound approximately one
turn around the magnetic layer 43 which constitutes part of the
second return path section 40. The magnetic head according to the
present embodiment is without the insulating layer 65.
As shown in FIG. 29, the second layer 122 includes a second coil
element 122A extending to pass between the magnetic layer 42 and
the magnetic layer 43, in particular, within the second space S2.
The second layer 122 has a coil connection part 122S penetrating
the insulating layer 63 and the insulating film 64 and electrically
connected to the coil connection part 21E (see FIG. 4) of the first
layer 21.
In the present embodiment, the magnetic layer 32 may be omitted as
in the third embodiment. The remainder of the configuration,
function and effects of the present embodiment are similar to those
of the first or third embodiment.
Fifth Embodiment
A magnetic head according to a fifth embodiment of the invention
will now be described with reference to FIG. 30. FIG. 30 is a
cross-sectional view of the magnetic head according to the present
embodiment. Note that FIG. 30 shows a cross section perpendicular
to the medium facing surface and to the top surface of the
substrate, or the main cross section, in particular.
The configuration of the magnetic head according to the present
embodiment is different from that of the magnetic head according to
the first embodiment in the following respects. The magnetic head
according to the present embodiment is without the electrode film
73. The first return path section 30 in the present embodiment
includes magnetic layers 33, 34 and 35 in place of the magnetic
layer 31 in the first embodiment. The magnetic layer 33 extends in
the direction perpendicular to the medium facing surface 80 and is
located closer to the top surface 1a of the substrate 1 than is the
first space S1. The magnetic layer 34 lies on a part of the
magnetic layer 33 in the vicinity of the medium facing surface 80,
and is located closer to the medium facing surface 80 than is the
first space S1. The magnetic layer 35 lies on a part of the
magnetic layer 33 away from the medium facing surface 80, and is
located farther from the medium facing surface 80 than are the
first space S1 and the magnetic layer 32. The first portion 10 of
the coil is wound approximately three turns around the magnetic
layers 32 and 35. The magnetic layer 34 has a first end face 34a
facing toward the medium facing surface 80 and a second end face
34b in contact with the write shield 16. The magnetic layer 35 has
an end face in contact with the magnetic layer 32 and an end face
in contact with the magnetic layer 36. The insulating film 53 is
interposed between the first portion 10 and each of the magnetic
layers 32 to 34.
The magnetic head according to the present embodiment has an
accommodation part 150 in place of the accommodation part 50 of the
first embodiment. The accommodation part 150 is made of a
nonmagnetic material and accommodates the magnetic layers 32 to 35
each constituting part of the first return path section 30. The
accommodation part 150 includes nonmagnetic layers 151, 152 and 153
stacked in this order on the middle shield layer 72. The
nonmagnetic layer 152 has an opening 152a that penetrates the
nonmagnetic layer 152 from its top surface to bottom surface. The
nonmagnetic layer 153 has an opening 153a that penetrates the
nonmagnetic layer 153 from its top surface to bottom surface. The
opening 153a has a first wall face located outside of the outermost
turn of the first portion 10 and a second wall face located inside
of the innermost turn of the first portion 10. The first and second
wall faces are inclined relative to the direction perpendicular to
the top surface 1a of the substrate 1. More specifically, in the
main cross section, the distance from the medium facing surface 80
to an arbitrary point on the first wall face decreases with
increasing distance from the arbitrary point to the top surface 1a
of the substrate 1. In the main cross section, the distance from
the medium facing surface 80 to an arbitrary point on the second
wall face increases with increasing distance from the arbitrary
point to the top surface 1a of the substrate 1.
The magnetic layer 33 is located in the opening 152a of the
nonmagnetic layer 152. The first portion 10 and the magnetic layers
32, 34 and 35 are located in the opening 153a of the nonmagnetic
layer 153. The top surfaces of the first portion 10, the magnetic
layers 32, 34 and 35, the insulating film 53, the insulating layer
54 and the nonmagnetic layer 153 are even with each other. The
nonmagnetic layers 151, 152 and 153 are each made of an inorganic
insulating material such as alumina.
The accommodation part 150 includes an interposer 150A interposed
between the first return path section 30 and the medium facing
surface 80. The interposer 150A has an inclined surface 150Aa
facing toward the first return path section 30. The inclined
surface 150Aa is formed by the first wall face of the opening 153a.
The distance from the medium facing surface 80 to an arbitrary
point on the inclined surface 150Aa decreases with increasing
distance from the arbitrary point to the top surface 1a of the
substrate 1. The magnetic layer 34 extends along the inclined
surface 150Aa. The magnetic layer 34 therefore corresponds to the
"inclined portion" according to the invention. The preferred range
of the angle formed by the inclined surface 150Aa relative to the
direction perpendicular to the top surface 1a of the substrate 1 is
the same as that formed by the inclined surface 50Aa of the first
embodiment relative to the direction perpendicular to the top
surface 1a of the substrate 1.
In the present embodiment, the second shield 16B is located on the
magnetic layer 34 and in contact with the end face 34a of the
magnetic layer 34. The magnetic layer 36 lies over the magnetic
layers 32 and 35.
The coil of the present embodiment may be configured to be
helically wound around the main pole 15 as in the second
embodiment. Alternatively, the second portion 20 of the coil of the
present embodiment may include the second layer 122 as in the
fourth embodiment. In the present embodiment, the magnetic layer 32
may be omitted as in the third embodiment. The remainder of the
configuration, function and effects of the present embodiment are
similar to those of the first to fourth embodiments.
The present invention is not limited to the foregoing embodiments,
and various modifications may be made thereto. For example, of the
first and second return path sections 30 and 40, only the first
return path section 30 may be provided in the magnetic head.
Furthermore, as far as the requirements of the appended claims are
met, the shapes and locations of the first return path section 30
and the accommodation part 50 are not limited to the examples
illustrated in the foregoing embodiments, and may be arbitrarily
chosen. For example, in the nonmagnetic layer 51 of the
accommodation part 50, the opening 51a may be replaced with a
groove having a bottom that is higher in level than the top surface
of the middle shield layer 72. In this case, the nonmagnetic film
52 may be omitted.
It is apparent that the present invention can be carried out in
various forms and modifications in the light of the foregoing
descriptions. Accordingly, within the scope of the following claims
and equivalents thereof, the present invention can be carried out
in forms other than the foregoing most preferred embodiments.
* * * * *